At present, in the display technical field, a backlight source, an LCD (Liquid Crystal Display) panel, a flexible circuit board and other elements are assembled together to realize display function. The backlight source and the LCD panel, or the backlight source and the flexible circuit board are respectively assembled to corresponding elements through a soldering process for example. During the manufacturing process, the soldering procedure of a backlight source and a flexible circuit board requires manual operations, however, it is hard to avoid poor soldering, internal solder connection, pseudo soldering or the other problems, and the rework caused by poor soldering and so on will give rise to losses of resources and materials such as flexible circuit boards, ICs and backlight sources. However, poor soldering, internal solder connection and pseudo soldering and other problems can not inspected directly by human eyes.